Facebook Pokes have been around since 2004, before most Facebook members ever joined the social network. Today Facebook announced a new way to Poke someone with an iPhone app that sends text, photo, or video messages that can be seen only for a limited time.

The self-destructing messages may remind users of classic spy movies, or more recently of the Snapchat application for Android and Apple iOS. Poke can send a text, photo, or video message that expires after 1, 3, 5, or 10 seconds. Once the clock runs out, the message is deleted from the phone and erased. The usefulness of such a feature seems limited, but Snapchat has skyrocketed in popularity using this same premise. Snapchat has been dogged by media accusations that it is an app geared for worry free "sexting" - sending explicit photos or videos of one's self to another person - but Poke is billed as a way to grab a friend's attention.

The original Facebook Poke website feature was a useless way to say "Hello" to a friend without actually typing anything. The Facebook iPhone app says "Hello" by actually sharing content with multiple people in private, which may be useful to someone looking to share something with a friend off the record. Poke requires that a user hold down to see content and alerts the sender if a recipient takes a screenshot. That provides little comfort once the content is already sent, but it can be a way to warn someone that the recipient may not be able to keep a secret.